"Back in the studio," she tweeted cryptically on Thursday, Jan. 10. "Uh oh..."

The 22-year-old's whirlwind romance with Styles, 18, went south last week during a vacation on Virgin Gorda, the largest of the British Virgin Islands, sources told Us Weekly. They had a fight -- after which Swift cut her holiday short and flew solo back to Nashville.

The Grammy-winning superstar didn't reveal any further details about her time in the studio, but she's been vocal about the fact that she regularly mines her personal relationships for new material. In the past, she has written songs about famous ex-flames including John Mayer, Jake Gyllenhaal, Taylor Lautner, and Joe Jonas.

"I've always lived by the theory that if a guy doesn't want me to write a bad song about him, he won't do bad things," she told Us in 2010. "And he shouldn't, you know?"